db = $db; * parent::__construct($config); * } * * public function findUser() * { * } * } * * class UserLister extends Object * { * public $finder; * * public function __construct(UserFinderInterface $finder, $config = []) * { * $this->finder = $finder; * parent::__construct($config); * } * } * * $container = new Container; * $container->set('yii\db\Connection', [ * 'dsn' => '...', * ]); * $container->set('app\models\UserFinderInterface', [ * 'class' => 'app\models\UserFinder', * ]); * $container->set('userLister', 'app\models\UserLister'); * * $lister = $container->get('userLister'); * * // which is equivalent to: * * $db = new \yii\db\Connection(['dsn' => '...']); * $finder = new UserFinder($db); * $lister = new UserLister($finder); * ``` * * @property array $definitions The list of the object definitions or the loaded shared objects (type or ID => * definition or instance). This property is read-only. * * @author Qiang Xue * @since 2.0 */ class Container extends Component { /** * @var array singleton objects indexed by their types */ private $_singletons = []; /** * @var array object definitions indexed by their types */ private $_definitions = []; /** * @var array constructor parameters indexed by object types */ private $_params = []; /** * @var array cached ReflectionClass objects indexed by class/interface names */ private $_reflections = []; /** * @var array cached dependencies indexed by class/interface names. Each class name * is associated with a list of constructor parameter types or default values. */ private $_dependencies = []; /** * Returns an instance of the requested class. * * You may provide constructor parameters (`$params`) and object configurations (`$config`) * that will be used during the creation of the instance. * * If the class implements [[\yii\base\Configurable]], the `$config` parameter will be passed as the last * parameter to the class constructor; Otherwise, the configuration will be applied *after* the object is * instantiated. * * Note that if the class is declared to be singleton by calling [[setSingleton()]], * the same instance of the class will be returned each time this method is called. * In this case, the constructor parameters and object configurations will be used * only if the class is instantiated the first time. * * @param string $class the class name or an alias name (e.g. `foo`) that was previously registered via [[set()]] * or [[setSingleton()]]. * @param array $params a list of constructor parameter values. The parameters should be provided in the order * they appear in the constructor declaration. If you want to skip some parameters, you should index the remaining * ones with the integers that represent their positions in the constructor parameter list. * @param array $config a list of name-value pairs that will be used to initialize the object properties. * @return object an instance of the requested class. * @throws InvalidConfigException if the class cannot be recognized or correspond to an invalid definition */ public function get($class, $params = [], $config = []) { if (isset($this->_singletons[$class])) { // singleton return $this->_singletons[$class]; } elseif (!isset($this->_definitions[$class])) { return $this->build($class, $params, $config); } $definition = $this->_definitions[$class]; if (is_callable($definition, true)) { $params = $this->resolveDependencies($this->mergeParams($class, $params)); $object = call_user_func($definition, $this, $params, $config); } elseif (is_array($definition)) { $concrete = $definition['class']; unset($definition['class']); $config = array_merge($definition, $config); $params = $this->mergeParams($class, $params); if ($concrete === $class) { $object = $this->build($class, $params, $config); } else { $object = $this->get($concrete, $params, $config); } } elseif (is_object($definition)) { return $this->_singletons[$class] = $definition; } else { throw new InvalidConfigException("Unexpected object definition type: " . gettype($definition)); } if (array_key_exists($class, $this->_singletons)) { // singleton $this->_singletons[$class] = $object; } return $object; } /** * Registers a class definition with this container. * * For example, * * ```php * // register a class name as is. This can be skipped. * $container->set('yii\db\Connection'); * * // register an interface * // When a class depends on the interface, the corresponding class * // will be instantiated as the dependent object * $container->set('yii\mail\MailInterface', 'yii\swiftmailer\Mailer'); * * // register an alias name. You can use $container->get('foo') * // to create an instance of Connection * $container->set('foo', 'yii\db\Connection'); * * // register a class with configuration. The configuration * // will be applied when the class is instantiated by get() * $container->set('yii\db\Connection', [ * 'dsn' => 'mysql:host=127.0.0.1;dbname=demo', * 'username' => 'root', * 'password' => '', * 'charset' => 'utf8', * ]); * * // register an alias name with class configuration * // In this case, a "class" element is required to specify the class * $container->set('db', [ * 'class' => 'yii\db\Connection', * 'dsn' => 'mysql:host=127.0.0.1;dbname=demo', * 'username' => 'root', * 'password' => '', * 'charset' => 'utf8', * ]); * * // register a PHP callable * // The callable will be executed when $container->get('db') is called * $container->set('db', function ($container, $params, $config) { * return new \yii\db\Connection($config); * }); * ``` * * If a class definition with the same name already exists, it will be overwritten with the new one. * You may use [[has()]] to check if a class definition already exists. * * @param string $class class name, interface name or alias name * @param mixed $definition the definition associated with `$class`. It can be one of the following: * * - a PHP callable: The callable will be executed when [[get()]] is invoked. The signature of the callable * should be `function ($container, $params, $config)`, where `$params` stands for the list of constructor * parameters, `$config` the object configuration, and `$container` the container object. The return value * of the callable will be returned by [[get()]] as the object instance requested. * - a configuration array: the array contains name-value pairs that will be used to initialize the property * values of the newly created object when [[get()]] is called. The `class` element stands for the * the class of the object to be created. If `class` is not specified, `$class` will be used as the class name. * - a string: a class name, an interface name or an alias name. * @param array $params the list of constructor parameters. The parameters will be passed to the class * constructor when [[get()]] is called. * @return $this the container itself */ public function set($class, $definition = [], array $params = []) { $this->_definitions[$class] = $this->normalizeDefinition($class, $definition); $this->_params[$class] = $params; unset($this->_singletons[$class]); return $this; } /** * Registers a class definition with this container and marks the class as a singleton class. * * This method is similar to [[set()]] except that classes registered via this method will only have one * instance. Each time [[get()]] is called, the same instance of the specified class will be returned. * * @param string $class class name, interface name or alias name * @param mixed $definition the definition associated with `$class`. See [[set()]] for more details. * @param array $params the list of constructor parameters. The parameters will be passed to the class * constructor when [[get()]] is called. * @return $this the container itself * @see set() */ public function setSingleton($class, $definition = [], array $params = []) { $this->_definitions[$class] = $this->normalizeDefinition($class, $definition); $this->_params[$class] = $params; $this->_singletons[$class] = null; return $this; } /** * Returns a value indicating whether the container has the definition of the specified name. * @param string $class class name, interface name or alias name * @return boolean whether the container has the definition of the specified name.. * @see set() */ public function has($class) { return isset($this->_definitions[$class]); } /** * Returns a value indicating whether the given name corresponds to a registered singleton. * @param string $class class name, interface name or alias name * @param boolean $checkInstance whether to check if the singleton has been instantiated. * @return boolean whether the given name corresponds to a registered singleton. If `$checkInstance` is true, * the method should return a value indicating whether the singleton has been instantiated. */ public function hasSingleton($class, $checkInstance = false) { return $checkInstance ? isset($this->_singletons[$class]) : array_key_exists($class, $this->_singletons); } /** * Removes the definition for the specified name. * @param string $class class name, interface name or alias name */ public function clear($class) { unset($this->_definitions[$class], $this->_singletons[$class]); } /** * Normalizes the class definition. * @param string $class class name * @param string|array|callable $definition the class definition * @return array the normalized class definition * @throws InvalidConfigException if the definition is invalid. */ protected function normalizeDefinition($class, $definition) { if (empty($definition)) { return ['class' => $class]; } elseif (is_string($definition)) { return ['class' => $definition]; } elseif (is_callable($definition, true) || is_object($definition)) { return $definition; } elseif (is_array($definition)) { if (!isset($definition['class'])) { if (strpos($class, '\\') !== false) { $definition['class'] = $class; } else { throw new InvalidConfigException("A class definition requires a \"class\" member."); } } return $definition; } else { throw new InvalidConfigException("Unsupported definition type for \"$class\": " . gettype($definition)); } } /** * Returns the list of the object definitions or the loaded shared objects. * @return array the list of the object definitions or the loaded shared objects (type or ID => definition or instance). */ public function getDefinitions() { return $this->_definitions; } /** * Creates an instance of the specified class. * This method will resolve dependencies of the specified class, instantiate them, and inject * them into the new instance of the specified class. * @param string $class the class name * @param array $params constructor parameters * @param array $config configurations to be applied to the new instance * @return object the newly created instance of the specified class */ protected function build($class, $params, $config) { /* @var $reflection ReflectionClass */ list ($reflection, $dependencies) = $this->getDependencies($class); foreach ($params as $index => $param) { $dependencies[$index] = $param; } $dependencies = $this->resolveDependencies($dependencies, $reflection); if (empty($config)) { return $reflection->newInstanceArgs($dependencies); } if (!empty($dependencies) && $reflection->implementsInterface('yii\base\Configurable')) { // set $config as the last parameter (existing one will be overwritten) $dependencies[count($dependencies) - 1] = $config; return $reflection->newInstanceArgs($dependencies); } else { $object = $reflection->newInstanceArgs($dependencies); foreach ($config as $name => $value) { $object->$name = $value; } return $object; } } /** * Merges the user-specified constructor parameters with the ones registered via [[set()]]. * @param string $class class name, interface name or alias name * @param array $params the constructor parameters * @return array the merged parameters */ protected function mergeParams($class, $params) { if (empty($this->_params[$class])) { return $params; } elseif (empty($params)) { return $this->_params[$class]; } else { $ps = $this->_params[$class]; foreach ($params as $index => $value) { $ps[$index] = $value; } return $ps; } } /** * Returns the dependencies of the specified class. * @param string $class class name, interface name or alias name * @return array the dependencies of the specified class. */ protected function getDependencies($class) { if (isset($this->_reflections[$class])) { return [$this->_reflections[$class], $this->_dependencies[$class]]; } $dependencies = []; $reflection = new ReflectionClass($class); $constructor = $reflection->getConstructor(); if ($constructor !== null) { foreach ($constructor->getParameters() as $param) { if ($param->isDefaultValueAvailable()) { $dependencies[] = $param->getDefaultValue(); } else { $c = $param->getClass(); $dependencies[] = Instance::of($c === null ? null : $c->getName()); } } } $this->_reflections[$class] = $reflection; $this->_dependencies[$class] = $dependencies; return [$reflection, $dependencies]; } /** * Resolves dependencies by replacing them with the actual object instances. * @param array $dependencies the dependencies * @param ReflectionClass $reflection the class reflection associated with the dependencies * @return array the resolved dependencies * @throws InvalidConfigException if a dependency cannot be resolved or if a dependency cannot be fulfilled. */ protected function resolveDependencies($dependencies, $reflection = null) { foreach ($dependencies as $index => $dependency) { if ($dependency instanceof Instance) { if ($dependency->id !== null) { $dependencies[$index] = $this->get($dependency->id); } elseif ($reflection !== null) { $name = $reflection->getConstructor()->getParameters()[$index]->getName(); $class = $reflection->getName(); throw new InvalidConfigException("Missing required parameter \"$name\" when instantiating \"$class\"."); } } } return $dependencies; } }